Window assembly

ABSTRACT

A tri-panel window assembly having a laterally movable center window panel and two opposed swingable side window panels mounted in vertical alignment within a stationary window frame. The center panel is suspended from an overhead track and is displaceable toward either end of the window frame when a respective independently pivotable side panel has been swung into an outwardly open position. The movement of the center panel provides an open space for emergency egress and ingress and facilitates access to the outer side of the window glass for cleaning. A safety bar housed in each of two mullions, which form part of the window frame extending vertically and offset interiorly on either side of the center panel, is automatically released by movement of a corresponding side panel and descends into a horizontal position between the two mullions. A locking arrangement mounted to the mullion secures the side panels which interlock with the center panel whereby a band of insulation packing around the panels is compressively held against the stationary frame to form a thermal and vapor barrier.

O United Stes atet 1 1 1 3,852,915

Schacht Dec. 10, 1974 WINDOW ASSEMBLY able center window panel and twoopposed swingable [76] Inventor: Louis L. Schacht, 205 E. 63rd St., f "Ypanels moumed in Vertical alignmer, New York NY 10021 w1th1n astat1onary wmdow frame. The center panel 1s suspended from an overheadtrack and is displaceable Filedi y 24, 1974 toward either end of thewindow frame when a respec- [21] APP] No: 473,011 tive independentlypivotable side panel has been swung into an outwardly open pos1t1on. Themove- 1 ment of the center panel provides an open space for 49/394emergency egress and ingress and facilities access to [51] Int. Cl E06b3/32 the gut r ide of the window glass for cleaning A Field of seal'dl49/128, 130, 142, 143, safety bar housed in each of two mullions, whichform 49/209, 394140114111 50; 52/207 part of the window frame extendingvertically and offset interiorly on either side of the center panel, is[56] References Cited afit omatically released by movement of a corre-UNITED STATES PATENTS sponding side panel and descends into a horizontal1,169,142 1/1916 Free 49/142 position between the two mullions- Alocking 1,997,556 4/1935 Beauchamp v 49/143 rangement mounted to themullion secures the side 1 8/1961 Henfikson fit 49/143 jjiiis whichinterlock with the center panel whereby 3,439,452 4/1969 Kain 49/143 aband fi l i packing around the paws is Primary ExaminerPhilip C. KannanAttorney, Agent, or FirmNatter & Natter, Esqs [57] ABSTRACT A tri-panelwindow assembly having a laterally movpressively held against thestationary frame to form a thermal and vapor barrier.

10 Claims, 7 Drawing Figures PATENTEU DEC 10 I974 1 WINDOW ASSEMBLYBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to closures and especially to a fenestration device or windowassembly.

The invention is further directed to a window assembly having pluralwindow panels mounted for diverse movement.

In particular, this invention concerns a window assembly having threewindow sashes with two of the sashes being mounted for independentpivotal movement and a third sash being laterally movably therebetweenin either of two directions.

DESCRIPTION OF THE PRIOR ART The plural window closures of the priorart, which included movable components, generally utilize either sasheswhich were slidable on separate tracks or employ swingable windows. Thepreviously used slidable sash windows move either horizontally orvertically and have been found to be rather inefficient in providing athermal and vapor barrier. This is because the ribbons of insulationmaterial or weather stripping placed on these window sashes frequentlybecomes worn or deteriorated through frictional contact with the trackwithin which the sash is mounted. Also, continuous rubbing at theinterface between adjacent sashes as the sashesby-pass each otherfurther abrades the insulation material. As a result, these windowsashes have been commonly found to develop water and air leaks as wellas being noisy and subject to rattles and vibrations. A reason for thesedifficulties lies in the fact that, because they are track mounted, aneffective compression seal can not be applied between the window sashand stationary frame when the window sashes are in the closed .position.A further disadvantage results from the fact that the tracks or guidesin which these window sashes slide frequently become sticky or tacky orswell due to moisture. Also, obstructions such as snow or ice prevent orhinder sliding movement of the sash.

Although conventional casement type windows employ swingable panels,these windows do not have the added features described in connectionwith this improved window assembly. For example, access to the weatherside of these windows is difficult and cumbersome. Additionally, thecurrently available swingable windows do not incorporate laterallydisplaceable panels or safety barriers.

The window assembly of the present invention overcomes many of thedisadvantages and defficiencies of the windows described in the priorart while supplying the construction industry with an economicallyfeasible window closure readily adaptable for many types of buildings. 1

The instant window assembly has been designed to provide an improvedweather seal, to facilitate access for cleaning, to provide emergencyingress and egress, and to incorporate safety features previouslyunavailable. Accordingly, the window assembly encompasses a combinationof swingable and laterally movable window sashes mounted in verticalalignment and utilizes an overhead track in the window frame whereby thecenter sash does not by-pass the swingable sash but rather occupies thesame space after the swingable sash has been displaced to an outwardlyopen position. Consequently, wiping contact of insulation packing orweather stripping and resultant deformation and deterioration areminimized. In this connection, a band of resilient insulation packing isplaced peripherally around the inside of each of the window sashes. Alocking arrangement for securing the sashes is adapted to compressivelyhold the resilient insulation material in contact with the stationaryframe member. Additionally, conductive heat loss is controlled byproviding insulation surrounding the glass pane or light where it ismounted within the window sash.

Another advantage of this invention is that the center sash is suspendedfrom an overhead track, as opposed to being slidably mounted in a lowertrack, and thus is not subject to obstructions in a lower track whichwould impede sliding movement.

A further advantage incorporated into the window assembly includes thesafety bar or guard barrier which is designed to automatically descendto a horizontal position across the center opening when a side sash hasbeen swung open.

It is also a feature of this invention that operating mechanisms havebeen included to position the side sash in various open or ventilatingpositions.

SUMMARY OF THE INVENTION Briefly, the invention involves a pluralclosure window assembly for a wall opening. A substantially rectangularstationary frame member surrounding the wall opening is designed tosupport three window panels or sashes, with each sash being adapted fordiverse movement. Two opposed end or side sashes are each pivotallysecured to an upright or jamb portion of the stationary frame so thateach can be swung outwardly in a respective clockwise orcounterclockwise direction. A center sash is suspended from an overheadtrack such that the center and two side sashes are substantially in thesame vertical plane when they are in the closed position, however thecenter panel is optionally movable toward either side of the stationaryframe after the respective side sash has been swung outwardly to theopen position. When the center sash is moved, the open span, formerlyoccupied by the center panel, provides access to the window sashes forcleaning and emergency egress or ingress.

An important feature of the invention relates to the automaticallyoperating safety bar which is activated by the pivotal movement ofeither side sash. Companion safety bars are housed in mullions whichform part of the stationary frame, interiorly and on either side of thecenter sash. Each of the side sashes contains a projecting retainermember which holds the safety bar in the stored position. Upon pivotalmovement of the side sash, the retainer is withdrawn and releases thesafety bar so that it is free to descend in a vertical plane to ahorizontal position across the center opening between the two mullions.

Another feature of the present invention relates to the lockingmechanism wherein a latch is pivotally mounted on the mullion and isadapted for engaging the side sash and pulling it toward the stationaryframe to compress the resilient band of insulation packing and achieve atight seal. The side window sash is movable with an operating handle,one end of which is securable to the sill for holding the sash in afixed open position. Alternatively, an optional stay rod mounted to themullion may be attached to the sash to hold it in a partially open orventilating position. The stay rod extends across the guide and thusprevents lateral movement of the center panel. When the side sash is inthe .fully open position, and has swung to its maximum disper or cushionplate in the lower portion of the guide.

It is an object of the instant invention to provide a plural closurehaving window sashes adapted for diverse movements.

Specifically, it is an object of this invention to provide a tri-panelwindow assembly wherein two opposed side window sashes are attached forswinging movement and a center window sash is mounted for lateralmovement.

It is a further object of the present invention to provide awindowassembly having improved vapor and thermal barriers wherein acompressive seal is achieved by a resilient band of insulation packingon a movable sash at the interface with a stationary frame.

Another object of this invention is to provide window assembly whereinthe outer or weather side of the window pane can be cleaned from insideof the building through an open span provided by lateral movement of thecenter sash.

An additional object of this invention is to provide a window assemblywherein a safety bar is automatically interposed adjacent the centersash when the said window sash is swung open.

Another object of the present invention is to provide a window assemblywherein thermal conductivity transmitted between the interior andexterior environment through the sash is minimized.

The above and other objects, features and advantages of the presentinvention will be apparent in the following description of the preferredembodiment when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings in whichare shown some of the possible embodiments of the invention:

FIG. 1 is an isometric view of the window assembly of this inventionincluding sections broken out and shows a right side sash in the fullyopen position, the left side sash in the closed and locked position, andthe center sash partially moved to the right with the safety bar, housedin the right mullion, descended to a horizontal disposed position;

FIG. 2 is a sectional view to an enlarged scale taken substantiallyalong line 2-2 of FIG. 1 with the sashes closed and shows the resilientinsulation packing surrounding the inside of the window sashes includinga safety bar stored with a mullion and a safety bar retainer tongueextending from the sash;

FIG. 3 is a sectional view to an enlarged scale taken substantiallyalong line 3-3 of FIG. 1 and shows the side sash in an open position andthe center sash laterally displaced;

FIG. 4 is a sectional view to an enlarged scale taken substantiallyalong lines 4-4 of FIG. 1 and shows the center sash suspended from anoverhead track of the frame member and mounted on rollers for lateralmovement;

FIG. 5 is a sectional view to an enlarged scale, taken substantiallyalong line 5-5 of FIG. 1 and shows the side sash in a closed and lockedposition forming a compressive seal between the resilient band ofinsulation-packing and the stationary frame; the safety bar retainer isshown extending into the mullion and securing the safety bar in avertical position housed within the channel shaped mullion;

FIG. 6 is a sectional view to an enlarged scale, taken through themullions along line 6-6 of FIG. I, and shows the two mullions with onesafety bar interposed in a horizontal operational position and the otherhoused in a vertical position;

FIG. 7 is an auxiliary sectional view to an enlarged scale, takensubstantially along line 7-7 of FIG. 6, and shows the descended safetybar seated on a pin or transverse shaft within the mullion and thehoused safety bar in the vertical position being held by the retainerextending from the side sash and cut-away portion of the mullion forreceiving the retainer.

DETAILED DESCRIPTION OF THE INVENTION Referring now in detail to thedrawings, the reference numeral 10 denotes generally a window assemblyconstructed in accordance with this invention. The window assembly 10 iscomprised ofa stationary frame member 12 which borders a wall openingand is permanently affixed to the wall. The frame 12 is generallyrectangular in shape having two parallel opposed upright verticalsections or jambs 14, 16, an upper horizontal section or litel 18, and alower horizontal section or still 20. A pair of vertical narrowchannel-shaped sections or mullions 22, 24 form part of the frame 12 andare disposed between the lintel 18 and sill 20 with opposed channelopenings facing each other.

The frame member 12 is preferably fabricated from extruded aluminum,being light in weight and having structural rigidity and economy;however, stainless steel or like materials may also be utilized.

The window assembly 10, as illustrated in FIG. 1, includes two sidewindow panels or sashes 26, 28 and a center panel or sash 30. Each ofthe side sashes 26, 28 is pivotally affixed to the respective windowjambs l4, 16 by a plurality of double leaf hinges 32 or equivalenthardware. As shown in FIGS. 2 and 3, a filler member 34 is placedbetween the jambs l4, l6 and the hinges 32 so that the vertical edge ofthe side sash 26, 28 will lie flush against jambs 14, 16 when in theclosed position.

Although a preferred embodiment of the invention is illustrated ashaving three sashes 26, 28, 30, the window assembly 10 is equallyadapatable for use with two sashes, one being swingable and the otherbeing slidable or laterally movable; such application should be readilyapparent from the following description of the invention.

The center sash 30 is suspended from an overhead track 36 formed in thelintel 18 and extending between the two jambs 14, 16. It should be notedthat the three sashes 26, 28, 30, when closed, will lie substantially inthe same vertical plane. A conveyor mechanism 38 is housed within thelintel l8 and may include a chain, belt or, as illustrated, a pluralityof wheels or rollers, preferably fabricated of durable hard rubber ornylon. A hanger member 40, carried by the conveyor 38, is attachable toand supports the center sash 30 for lateral movement in the verticalplane. The lower portion of the center sash clears a ledge 42 formed inthe sill 20. A plurality of spaced guides 46, are affixed to the outerledge 42 between the mullions 22, 24, and prevent the lower portion ofthe sash 30 from swinging outwardly. Although the guides 46 do notextend along the ledge 42 adjacent the side sashes 26, 28, at least oneguide 46 will contact and restrain the center sash 30 even after it hasbeen laterally moved to its maximum displacement. It sould be mentioned,that the guides 46 are so positioned to provide a clearance widthgreater than the thickness of the center sash 30 to reduce rubbingcontact.

A continuous relatively wide band of resilient insulation packing orweather stripping 44, preferably made of compressible Neoprene or rubbercomposition, is secured peripherally and within a pocket formed on theinner face of center sash 30. In a similar manner, the insulationpacking 44 is secured to the side sashes 26, 28. During opening orclosing of the sashes 26, 28, 30, the insulation packing 44 isrelatively free of wiping contact, especially since there is no by-passof the side sashes 26, 28 by the center sash; therefore, frictionalcontact between the insulation material 44 and adjacent surfaces isminimized. In this regard, it should also be observed that obstructions,such as dirt, ice, snow or other foreign matter, present on ledge 42,will not readily impede lateral movement because the center sash 30 doesnot rest or slide on the bottom ofledge 42; additionally, a slight pitchis provided to ledge 42 for drainage and run-off.

The swingable side sashes 26, 28 are disposed in vertical alignment withthe center sash 30 and slightly above the ledge 42 so that the bottom ofthe sash 26, 28 will clear the ledge 42. Thus, when the swingable sidesashes 26, 28 are swung outwardly, the center sash 30 will bedisplaceable into the area previously occupied by the' side sashes26,28. The limit of lateral displacement of the center sash 30 towardeither of the side sashes 26, 28, is determined by a bumper or cushionplate 48 which is fixedly positioned on ledge 42. In this connection,the maximum swingable displacement of the side sashes 26, 28 is likewiselimited to about 30 from the closed position; accordingly, a stop member50 is affixed to the ledge 42 which arrests the movement.

The sashes 26, 28, 30 are glazed or fitted with a pane or light oftransparent glass 52 which is secured within a groove 54. A pliablesealer 56 substance such as *Everseal or other bituminous materialplaced around the edges of the glass pane 52 is designed to expand as ithardens. Shims or moulding may also be used in conjunction with thesealer 56. In contrast to conventional putty or calking, th sealer 56provides substantial insulation qualities to reduce thermal transferencefrom opposite sides of the glass pane 52 through adjacent sections ofthe sashes.

The movement of the side sash 26, 28 is controlled by an operatinghandle 58, 60 which is pinned at one end to the sash 26, 28 to permituniversal motion. The outer end of the handle 58, 60 is keyed forreception in a recess 62, 64 when the sash is in a closed position. Theside window sash 26, 28 is swingable to an open position by a push-pullmanipulation ofthe operating handle 58, 60 and by the subsequentsecurement of the keyed end in a respective slot 66, 68 formed in theledge 42. Additionally, as an optional feature, a stay rod 70, 72 ismounted to the mullion 22, 24 and is extendible across the ledge 42 forengagement within a locking slot 74, 76 in the side sash 26, 28 tosecure the sash in an intermediate open or ventilating position. Itshould be noted that the center sash 30 can not be laterally moved inthe direction of the open sash because of interference with the stay rod70, 72, thus avoiding possible damaging contact between the sashes and apotential safety hazard.

The window sashes 26, 28, 30 are lockable in vertical alignment by alatch 76 mounted on the mullion 22, which engages a catch 78 on the sidesash 26. A latch (not shown) on mullion 24 similarly engages a catch onside sash 28. The side sashes 26, 28 have an overlapping flange 80, 82which interlocks with the edges of the center sash 26 so that all threesashes 26, 28, 30 are simultaneously urged against the stationary frame12. It should thus be apparent that, upon locking the side sashes, thecontinuous band ofinsulation packing 44 on the inner face of all threesashes is compressed to form a tight seal impervious to thermal or vaporpassage.

A particularly important improvement of the present window assembly It)relates to safety features which have been incoporated and whichsubstantially reduces any danger presented when the center sash 30 hasbeen moved to either side leaving an open center span. A pair ofprotective guards or safety bars 84, 86 automatically descend, uponopening of either side sash 26, 28 from a vertical position withinrespective mullions 22, 24 to a horizontal position across the open spanbetween the mullions 22, 24. Each of the safety bars 84, 86 is rotatablymounted on a pin 88, 90 in respective mullions 22, 24 such that, whenthe safety bar is housed in the vertical storage positon within themullions 22, 24, the pivot point is offset from line passing through thecenter of gravity of the bar and there is a gravitational force vectortending to rotate the bar into the horizontal operational position. Themovement of the bar, however, can also be accomplished by spring orother resilient urging devices. As illustrated in FIG. 7, a free end ofthe safety bar 86 has a recess 92 which seats on the pin 88 in thecompanion mullion 22. The safey bar 86 may be manually returned to thevertical position and is held within the mullion 24 by a retainer 94which is affixed to and projects from the side window sash 28. A portionof the side and back wall of the channel-shaped mullion 24 is cut out at96 to allow th retainer 94 to enter and withdraw from the mullion 24upon closing or opening of the side sash 28. The retainer 94 contacts atail segment 98 of the safety bar 86 and thereby prevents its rotationinto the horizontal position. When the side sash 28 is opened, however,the retainer 94 is withdrawn to release the safety bar 86 which thenautomatically descends into the horizontal position and the tail segment98 may be extendible through the cut-out section 96. The safety bar 84operates in a similar manner and is released by a retainer 100projecting from sash 26 which enters a cut out portion 102 of mullion 22to contact a tail segment 104. The retainer 94, 100 is preferablycomprised of a tongue of phosphorus bronze material having the necessaryrigidity to hold the safety bar 84, 86 within the mullion 22, 24, yet isflexible enough to provide the requisite spring action and resiliency aswhen entering or being withdrawn from the mullion 22, 24. The inventionalso contemplates the introduction of a damper" to control the descentor fall of the safety bar. It is also apparent that spring urging meanscan be incorporated for retaining or releasing the barrier from themullion and, additionally, cushioning material can be incorporated forsoftening contact between the safety bar and the shaft upon which thebar is seated.

The above cited embodiment is intended as exemplary; and while it hasdescribed the invention with a specific implementation thereof, othermodifications and various changes might be made in the embodiment as soset forth and will be apparent to those skilled in the art. It should,therefore, be understood that all material described or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

Having thus described the invention, there is claimed as new and desiredto be secured by Letters Patent:

1. A plural closure window assembly for a wall opening adapted forproviding ventilation and access to the weather side of the windowassembly, comprising a rectangular frame member securable along a marginof the wall opening and including at least two sash members, a firstsash member being mounted for lateral movement within the frame member,a second sash member being pivotally attached along one vertical side ofthe frame member, sealing means foreffecting a vapor and thermal barrierat the interface between the sash members and the frame member, thesecond sash being swingable from an initially closed position in asubstantially coincident vertical plane with the first sash member to anoutwardly open position, the first sash member being selectivelydisplaceable within the vertical plane into the space previouslyoccupied by the closed second sash member to thereby define an open spanfor providing access exteriorly of the wall and further including safetymeans for forming a protective barrier across the open span, said safetymeans being deployable upon movement of the second sash member.

2. A plural closure window assembly as claimed in claim 1 comprised ofthree sash members, the third sash member being pivotally attached alongthe other vertical side of the frame member and being swingable in adirection counter to the rotation of the second sash member, from anintially closed position in a substantially coincident vertical planewith the second sash member to an outwardly open position, the firstcenter sash member being selectively displaceable laterally within thevertical plane optionally toward either side of the frame member intothe space previously occupied by either of the closed second or thirdsash members to thereby define an open span for providing accessexteriorly of the wall.

3. A plural closure window assembly as claimed in claim 2 furtherincluding two mullions positioned vertically within the frame member,the mullions being spaced at the juncture between the first sash and thetwo pivotal sashes and parallelto the plane of the sashes, the safetymeans comprising at least one elongated barrier member descendable froma vertical storage position within the mullion to a horizontal positionbetween the two mullions to provide a protective barrier across the openspan.

4. A plural closure, window assembly as claimed in claim 3 furtherincluding safety barrier release means comprising retainer means on thepivotal sash adapted for cooperative engagement with the barrier memberwithin the mullion for retention in the vertical storage position, saidretainer means being disengaged by the swingable movement of the pivotalsash to automatically release the barrier member for deployment betweenthe two mullions.

5. A plural closure window assembly as claimed in claim 4 wherein thesafety barrier mounted within the mullion is urged from the verticalstorage position toward the horizontal operational position, and theretainer means includes a resilient tongue projecting from the pivotalsash and adapted to extend through an opening in the mullion to engage aportion of the safety barrier when the pivotal sash is closed, saidbarrier being released upon withdrawal of the tongue as the swingablesash is opened.

6. A plural closure window assembly as claimed in claim 4 wherein eachmullion has a companion elongated barrier member, the barrier membersbeing rotatably mounted on a pin within the mullion and beingindependently releasable by the respective retainer member anddescendable into horizontal deployment wherein the barrier definestherein a recess at one end engageable on a pin within the correspondingmullion upon which the companion elongated barrier member is mounted.

7. A plural closure window assembly as claimed in claim 2 including anoverhead track in the frame member, conveyor means within the track forsuspending the first sash for lateral movement, guide means on the lowerhorizontal portion of the frame member for restraining outward movementof the first sash and providing a clearance width greater than thethickness of the first sash, wherein frictional contact at the interfacebetween the frame member and the sealing means on the lateral movablesash is minimized.

8. A plural closure window assembly'as claimed in claim 1 wherein thesealing means includes a continuous band of resilient insulation packingplaced interiorly around the inner face of the sashes, further includinglocking means on the frame member for releasably engaging the pivotalsashes, and interlocking means on the pivotal sashes for cooperativeengagement of the center sash to simultaneously compress the insulationpacking on the sashes against the frame member to form a weathertightseal.

9. A plural closure window assembly as claimed in claim 3 furtherincluding an operating handle on the pivotal sash for opening andclosing the sash and for retaining the sash in an open position wherebythe center sash is laterally movable, and further including stop meansfor limiting maximum swingable displacement of the pivotal sash andabutment means for limiting maximum lateral movement of the center sash.

10. A plural closure window assembly as claimed in claim 9 furtherincluding a stay means for holding the pivotal window in a fixed openposition and for preventing lateral movement of the center sash.

1. A plural closure window assembly for a wall opening adapted forproviding ventilation and access to the weather side of the windowassembly, comprising a rectangular frame member securable along a marginof the wall opening and including at least two sash members, a firstsash member being mounted for lateral movement within the frame member,a second sash member being pivotally attached along one vertical side ofthe frame member, sealing means for effecting a vapor and thermalbarrier at the interface between the sash members and the frame member,the second sash being swingable from an initially closed position in asubstantially coincident vertical plane with the first sash member to anoutwardly open position, the first sash member being selectivelydisplaceable within the vertical plane into the space previouslyoccupied by the closed second sash member to thereby define an open spanfor providing access exteriorly of the wall and further including safetymeans for forming a protective barrier across the open span, said safetymeans being deployable upon movement of the second sash member.
 2. Aplural closure window assembly as claimed in claim 1 comprised of threesash members, the third sash member being pivotally attached along theother vertical side of the frame member and being swingable in adirection counter to the rotation of the second sash member, from anIntially closed position in a substantially coincident vertical planewith the second sash member to an outwardly open position, the firstcenter sash member being selectively displaceable laterally within thevertical plane optionally toward either side of the frame member intothe space previously occupied by either of the closed second or thirdsash members to thereby define an open span for providing accessexteriorly of the wall.
 3. A plural closure window assembly as claimedin claim 2 further including two mullions positioned vertically withinthe frame member, the mullions being spaced at the juncture between thefirst sash and the two pivotal sashes and parallel to the plane of thesashes, the safety means comprising at least one elongated barriermember descendable from a vertical storage position within the mullionto a horizontal position between the two mullions to provide aprotective barrier across the open span.
 4. A plural closure windowassembly as claimed in claim 3 further including safety barrier releasemeans comprising retainer means on the pivotal sash adapted forcooperative engagement with the barrier member within the mullion forretention in the vertical storage position, said retainer means beingdisengaged by the swingable movement of the pivotal sash toautomatically release the barrier member for deployment between the twomullions.
 5. A plural closure window assembly as claimed in claim 4wherein the safety barrier mounted within the mullion is urged from thevertical storage position toward the horizontal operational position,and the retainer means includes a resilient tongue projecting from thepivotal sash and adapted to extend through an opening in the mullion toengage a portion of the safety barrier when the pivotal sash is closed,said barrier being released upon withdrawal of the tongue as theswingable sash is opened.
 6. A plural closure window assembly as claimedin claim 4 wherein each mullion has a companion elongated barriermember, the barrier members being rotatably mounted on a pin within themullion and being independently releasable by the respective retainermember and descendable into horizontal deployment wherein the barrierdefines therein a recess at one end engageable on a pin within thecorresponding mullion upon which the companion elongated barrier memberis mounted.
 7. A plural closure window assembly as claimed in claim 2including an overhead track in the frame member, conveyor means withinthe track for suspending the first sash for lateral movement, guidemeans on the lower horizontal portion of the frame member forrestraining outward movement of the first sash and providing a clearancewidth greater than the thickness of the first sash, wherein frictionalcontact at the interface between the frame member and the sealing meanson the lateral movable sash is minimized.
 8. A plural closure windowassembly as claimed in claim 1 wherein the sealing means includes acontinuous band of resilient insulation packing placed interiorly aroundthe inner face of the sashes, further including locking means on theframe member for releasably engaging the pivotal sashes, andinterlocking means on the pivotal sashes for cooperative engagement ofthe center sash to simultaneously compress the insulation packing on thesashes against the frame member to form a weathertight seal.
 9. A pluralclosure window assembly as claimed in claim 3 further including anoperating handle on the pivotal sash for opening and closing the sashand for retaining the sash in an open position whereby the center sashis laterally movable, and further including stop means for limitingmaximum swingable displacement of the pivotal sash and abutment meansfor limiting maximum lateral movement of the center sash.
 10. A pluralclosure window assembly as claimed in claim 9 further including a staymeans for holding the pivotal window in a fixed open position and forpreventing lateral movement of the center sash.